/*
Copyright 2021 - 2023 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import React, { createRef, KeyboardEvent } from "react";
import {
    Thread,
    THREAD_RELATION_TYPE,
    ThreadEvent,
    Room,
    RoomEvent,
    IEventRelation,
    MatrixEvent,
} from "matrix-js-sdk/src/matrix";
import { logger } from "matrix-js-sdk/src/logger";
import classNames from "classnames";

import BaseCard from "../views/right_panel/BaseCard";
import { RightPanelPhases } from "../../stores/right-panel/RightPanelStorePhases";
import ResizeNotifier from "../../utils/ResizeNotifier";
import MessageComposer from "../views/rooms/MessageComposer";
import { RoomPermalinkCreator } from "../../utils/permalinks/Permalinks";
import { Layout } from "../../settings/enums/Layout";
import TimelinePanel from "./TimelinePanel";
import dis from "../../dispatcher/dispatcher";
import { ActionPayload } from "../../dispatcher/payloads";
import { Action } from "../../dispatcher/actions";
import { MatrixClientPeg } from "../../MatrixClientPeg";
import { E2EStatus } from "../../utils/ShieldUtils";
import EditorStateTransfer from "../../utils/EditorStateTransfer";
import RoomContext, { TimelineRenderingType } from "../../contexts/RoomContext";
import ContentMessages from "../../ContentMessages";
import UploadBar from "./UploadBar";
import { _t } from "../../languageHandler";
import ThreadListContextMenu from "../views/context_menus/ThreadListContextMenu";
import RightPanelStore from "../../stores/right-panel/RightPanelStore";
import SettingsStore from "../../settings/SettingsStore";
import { ViewRoomPayload } from "../../dispatcher/payloads/ViewRoomPayload";
import FileDropTarget from "./FileDropTarget";
import { getKeyBindingsManager } from "../../KeyBindingsManager";
import { KeyBindingAction } from "../../accessibility/KeyboardShortcuts";
import Measured from "../views/elements/Measured";
import PosthogTrackers from "../../PosthogTrackers";
import { ButtonEvent } from "../views/elements/AccessibleButton";
import Spinner from "../views/elements/Spinner";
import { ComposerInsertPayload, ComposerType } from "../../dispatcher/payloads/ComposerInsertPayload";
import Heading from "../views/typography/Heading";
import { SdkContextClass } from "../../contexts/SDKContext";
import { ThreadPayload } from "../../dispatcher/payloads/ThreadPayload";

interface IProps {
    room: Room;
    onClose: () => void;
    resizeNotifier: ResizeNotifier;
    mxEvent: MatrixEvent;
    permalinkCreator?: RoomPermalinkCreator;
    e2eStatus?: E2EStatus;
    initialEvent?: MatrixEvent;
    isInitialEventHighlighted?: boolean;
    initialEventScrollIntoView?: boolean;
}

interface IState {
    thread?: Thread;
    lastReply?: MatrixEvent | null;
    layout: Layout;
    editState?: EditorStateTransfer;
    replyToEvent?: MatrixEvent;
    narrow: boolean;
}

export default class ThreadView extends React.Component<IProps, IState> {
    public static contextType = RoomContext;
    public context!: React.ContextType<typeof RoomContext>;

    private dispatcherRef: string | null = null;
    private readonly layoutWatcherRef: string;
    private timelinePanel = createRef<TimelinePanel>();
    private card = createRef<HTMLDivElement>();

    // Set by setEventId in ctor.
    private eventId!: string;

    public constructor(props: IProps) {
        super(props);

        this.setEventId(this.props.mxEvent);
        const thread = this.props.room.getThread(this.eventId) ?? undefined;

        this.setupThreadListeners(thread);
        this.state = {
            layout: SettingsStore.getValue("layout"),
            narrow: false,
            thread,
            lastReply: thread?.lastReply((ev: MatrixEvent) => {
                return ev.isRelation(THREAD_RELATION_TYPE.name) && !ev.status;
            }),
        };

        this.layoutWatcherRef = SettingsStore.watchSetting("layout", null, (...[, , , value]) =>
            this.setState({ layout: value as Layout }),
        );
    }

    public componentDidMount(): void {
        if (this.state.thread) {
            this.postThreadUpdate(this.state.thread);
        }

        this.setupThread(this.props.mxEvent);
        this.dispatcherRef = dis.register(this.onAction);

        this.props.room.on(ThreadEvent.New, this.onNewThread);
    }

    public componentWillUnmount(): void {
        if (this.dispatcherRef) dis.unregister(this.dispatcherRef);
        const roomId = this.props.mxEvent.getRoomId();
        SettingsStore.unwatchSetting(this.layoutWatcherRef);

        const hasRoomChanged = SdkContextClass.instance.roomViewStore.getRoomId() !== roomId;
        if (this.props.initialEvent && !hasRoomChanged) {
            dis.dispatch<ViewRoomPayload>({
                action: Action.ViewRoom,
                room_id: this.props.room.roomId,
                metricsTrigger: undefined, // room doesn't change
            });
        }

        dis.dispatch<ThreadPayload>({
            action: Action.ViewThread,
            thread_id: null,
        });

        this.state.thread?.off(ThreadEvent.NewReply, this.updateThreadRelation);
        this.props.room.off(RoomEvent.LocalEchoUpdated, this.updateThreadRelation);
        this.props.room.removeListener(ThreadEvent.New, this.onNewThread);
    }

    public componentDidUpdate(prevProps: IProps): void {
        if (prevProps.mxEvent !== this.props.mxEvent) {
            this.setEventId(this.props.mxEvent);
            this.setupThread(this.props.mxEvent);
        }

        if (prevProps.room !== this.props.room) {
            RightPanelStore.instance.setCard({ phase: RightPanelPhases.RoomSummary });
        }
    }

    private setEventId(event: MatrixEvent): void {
        if (!event.getId()) {
            throw new Error("Got thread event without id");
        }

        this.eventId = event.getId()!;
    }

    private onAction = (payload: ActionPayload): void => {
        if (payload.phase == RightPanelPhases.ThreadView && payload.event) {
            this.setupThread(payload.event);
        }
        switch (payload.action) {
            case Action.ComposerInsert: {
                if (payload.composerType) break;
                if (payload.timelineRenderingType !== TimelineRenderingType.Thread) break;

                // re-dispatch to the correct composer
                dis.dispatch<ComposerInsertPayload>({
                    ...(payload as ComposerInsertPayload),
                    composerType: this.state.editState ? ComposerType.Edit : ComposerType.Send,
                });
                break;
            }

            case Action.EditEvent:
                // Quit early if it's not a thread context
                if (payload.timelineRenderingType !== TimelineRenderingType.Thread) return;
                // Quit early if that's not a thread event
                if (payload.event && !payload.event.getThread()) return;
                this.setState(
                    {
                        editState: payload.event ? new EditorStateTransfer(payload.event) : undefined,
                    },
                    () => {
                        if (payload.event) {
                            this.timelinePanel.current?.scrollToEventIfNeeded(payload.event.getId());
                        }
                    },
                );
                break;
            case "reply_to_event":
                if (payload.context === TimelineRenderingType.Thread) {
                    this.setState({
                        replyToEvent: payload.event,
                    });
                }
                break;
            default:
                break;
        }
    };

    private setupThread = (mxEv: MatrixEvent): void => {
        /** presence of event Id has been ensured by {@link setEventId} */
        const eventId = mxEv.getId()!;

        let thread = this.props.room.getThread(eventId);

        if (!thread) {
            const events = [];
            // if the event is still being sent, don't include it in the Thread yet - otherwise the timeline panel
            // will attempt to show it twice (once as a regular event, once as a pending event) and everything will
            // blow up
            if (mxEv.status === null) events.push(mxEv);
            thread = this.props.room.createThread(eventId, mxEv, events, true);
        }

        this.updateThread(thread);
    };

    private onNewThread = (thread: Thread): void => {
        if (thread.id === this.props.mxEvent.getId()) {
            this.setupThread(this.props.mxEvent);
        }
    };

    private updateThreadRelation = (): void => {
        this.setState({
            lastReply: this.threadLastReply,
        });
    };

    private get threadLastReply(): MatrixEvent | undefined {
        return (
            this.state.thread?.lastReply((ev: MatrixEvent) => {
                return ev.isRelation(THREAD_RELATION_TYPE.name) && !ev.status;
            }) ?? undefined
        );
    }

    private updateThread = (thread?: Thread): void => {
        if (this.state.thread === thread) return;

        this.setupThreadListeners(thread, this.state.thread);
        if (thread) {
            this.setState(
                {
                    thread,
                    lastReply: this.threadLastReply,
                },
                async () => this.postThreadUpdate(thread),
            );
        }
    };

    private async postThreadUpdate(thread: Thread): Promise<void> {
        dis.dispatch<ThreadPayload>({
            action: Action.ViewThread,
            thread_id: thread.id,
        });
        thread.emit(ThreadEvent.ViewThread);
        this.updateThreadRelation();
        this.timelinePanel.current?.refreshTimeline(this.props.initialEvent?.getId());
    }

    private setupThreadListeners(thread?: Thread | undefined, oldThread?: Thread | undefined): void {
        if (oldThread) {
            this.state.thread?.off(ThreadEvent.NewReply, this.updateThreadRelation);
            this.props.room.off(RoomEvent.LocalEchoUpdated, this.updateThreadRelation);
        }
        if (thread) {
            thread.on(ThreadEvent.NewReply, this.updateThreadRelation);
            this.props.room.on(RoomEvent.LocalEchoUpdated, this.updateThreadRelation);
        }
    }

    private resetJumpToEvent = (event?: string): void => {
        if (
            this.props.initialEvent &&
            this.props.initialEventScrollIntoView &&
            event === this.props.initialEvent?.getId()
        ) {
            dis.dispatch<ViewRoomPayload>({
                action: Action.ViewRoom,
                room_id: this.props.room.roomId,
                event_id: this.props.initialEvent?.getId(),
                highlighted: this.props.isInitialEventHighlighted,
                scroll_into_view: false,
                replyingToEvent: this.state.replyToEvent,
                metricsTrigger: undefined, // room doesn't change
            });
        }
    };

    private onMeasurement = (narrow: boolean): void => {
        this.setState({ narrow });
    };

    private onKeyDown = (ev: KeyboardEvent): void => {
        let handled = false;

        const action = getKeyBindingsManager().getRoomAction(ev);
        switch (action) {
            case KeyBindingAction.UploadFile: {
                dis.dispatch(
                    {
                        action: "upload_file",
                        context: TimelineRenderingType.Thread,
                    },
                    true,
                );
                handled = true;
                break;
            }
        }

        if (handled) {
            ev.stopPropagation();
            ev.preventDefault();
        }
    };

    private onFileDrop = (dataTransfer: DataTransfer): void => {
        const roomId = this.props.mxEvent.getRoomId();
        if (roomId) {
            ContentMessages.sharedInstance().sendContentListToRoom(
                Array.from(dataTransfer.files),
                roomId,
                this.threadRelation,
                MatrixClientPeg.safeGet(),
                TimelineRenderingType.Thread,
            );
        } else {
            console.warn("Unknwon roomId for event", this.props.mxEvent);
        }
    };

    private get threadRelation(): IEventRelation {
        const relation: IEventRelation = {
            rel_type: THREAD_RELATION_TYPE.name,
            event_id: this.state.thread?.id,
            is_falling_back: true,
        };

        const fallbackEventId = this.state.lastReply?.getId() ?? this.state.thread?.id;
        if (fallbackEventId) {
            relation["m.in_reply_to"] = {
                event_id: fallbackEventId,
            };
        }

        return relation;
    }

    private renderThreadViewHeader = (): JSX.Element => {
        return (
            <div className="mx_BaseCard_header_title">
                <Heading size="4" className="mx_BaseCard_header_title_heading">
                    {_t("Thread")}
                </Heading>
                <ThreadListContextMenu mxEvent={this.props.mxEvent} permalinkCreator={this.props.permalinkCreator} />
            </div>
        );
    };

    public render(): React.ReactNode {
        const highlightedEventId = this.props.isInitialEventHighlighted ? this.props.initialEvent?.getId() : undefined;

        const threadRelation = this.threadRelation;

        let timeline: JSX.Element | null;
        if (this.state.thread) {
            if (this.props.initialEvent && this.props.initialEvent.getRoomId() !== this.state.thread.roomId) {
                logger.warn(
                    "ThreadView attempting to render TimelinePanel with mismatched initialEvent",
                    this.state.thread.roomId,
                    this.props.initialEvent.getRoomId(),
                    this.props.initialEvent.getId(),
                );
            }

            timeline = (
                <>
                    <FileDropTarget parent={this.card.current} onFileDrop={this.onFileDrop} />
                    <TimelinePanel
                        key={this.state.thread.id}
                        ref={this.timelinePanel}
                        showReadReceipts={this.context.showReadReceipts}
                        manageReadReceipts={true}
                        manageReadMarkers={true}
                        sendReadReceiptOnLoad={true}
                        timelineSet={this.state.thread.timelineSet}
                        showUrlPreview={this.context.showUrlPreview}
                        // ThreadView doesn't support IRC layout at this time
                        layout={this.state.layout === Layout.Bubble ? Layout.Bubble : Layout.Group}
                        hideThreadedMessages={false}
                        hidden={false}
                        showReactions={true}
                        className="mx_RoomView_messagePanel"
                        permalinkCreator={this.props.permalinkCreator}
                        membersLoaded={true}
                        editState={this.state.editState}
                        eventId={this.props.initialEvent?.getId()}
                        highlightedEventId={highlightedEventId}
                        eventScrollIntoView={this.props.initialEventScrollIntoView}
                        onEventScrolledIntoView={this.resetJumpToEvent}
                    />
                </>
            );
        } else {
            timeline = (
                <div className="mx_RoomView_messagePanelSpinner">
                    <Spinner />
                </div>
            );
        }

        return (
            <RoomContext.Provider
                value={{
                    ...this.context,
                    timelineRenderingType: TimelineRenderingType.Thread,
                    threadId: this.state.thread?.id,
                    liveTimeline: this.state?.thread?.timelineSet?.getLiveTimeline(),
                    narrow: this.state.narrow,
                }}
            >
                <BaseCard
                    className={classNames("mx_ThreadView mx_ThreadPanel", {
                        mx_ThreadView_narrow: this.state.narrow,
                    })}
                    onClose={this.props.onClose}
                    withoutScrollContainer={true}
                    header={this.renderThreadViewHeader()}
                    ref={this.card}
                    onKeyDown={this.onKeyDown}
                    onBack={(ev: ButtonEvent) => {
                        PosthogTrackers.trackInteraction("WebThreadViewBackButton", ev);
                    }}
                >
                    {this.card.current && <Measured sensor={this.card.current} onMeasurement={this.onMeasurement} />}
                    <div className="mx_ThreadView_timelinePanelWrapper">{timeline}</div>

                    {ContentMessages.sharedInstance().getCurrentUploads(threadRelation).length > 0 && (
                        <UploadBar room={this.props.room} relation={threadRelation} />
                    )}

                    {this.state.thread?.timelineSet && (
                        <MessageComposer
                            room={this.props.room}
                            resizeNotifier={this.props.resizeNotifier}
                            relation={threadRelation}
                            replyToEvent={this.state.replyToEvent}
                            permalinkCreator={this.props.permalinkCreator}
                            e2eStatus={this.props.e2eStatus}
                            compact={true}
                        />
                    )}
                </BaseCard>
            </RoomContext.Provider>
        );
    }
}
